What the subsidence revealed was a souterrain, an underground stone or earth-cut passage typically associated with early medieval settlement in Ireland, used variously for food storage, refuge, or both. The collapse happened during land reclamation work, which is, when you think about it, a fitting way for such a structure to reappear: disturbed by the same kind of agricultural ambition that may have driven its original construction over a thousand years ago.

At least two earth-cut chambers were identified, though both were found to be inaccessible, choked with debris from the roof that had given way. One detail stands out from what could be observed: a blocked-up construction shaft, the kind of opening used by builders to excavate and line the chambers from above before sealing the passage against the surface. Its presence is a small, legible trace of the labour involved in building something designed never to be easily seen. The site was subsequently infilled, returning the pasture on its west-facing slope to something resembling its pre-collapse appearance, with the chambers sealed beneath once more.